One of the flat panel displays more used in the current market is Liquid crystal display (LCD). The liquid crystal displays require various operating voltages during operation. The power management module of the driver circuit transforming the input voltage provides the operating voltage.
A common used power management module in the prior art is shown in FIG. 1. The Boost circuit, the buck circuit, the operation amplifier output circuit and the charge pump circuit are integrated in the power management ICs (PMIC) and the various required voltages are obtained by boosting, bucking, or amplifying the input voltage (Vin). In the driving circuit of the liquid crystal panel, two most common voltages are the analog supply voltage VAA and the digital supply voltage VDD. The analog voltage VAA is obtained from the boost circuit by boosting the input voltage Vin. The digital voltage is obtained from the buck circuit by bucking the input voltage Vin. Both of these two supply voltages are generated by two mutually independent circuits requiring more components. This kind of design not only increases production cost but also occupies a larger area in the integrated circuit.